This invention relates generally to a failure detection circuit for an X-ray tube power source, and relates more specifically to a failure detection circuit used in a high tension power source for a center metal grounded type X-ray tube.
In a typical known power source used for the X-ray tube of which the center metal is grounded, there is provided a switching element such as a tetrode between either the anode or the cathode of the X-ray tube and the high tension power source, which is used to control the X-ray radition projected from the X-ray tube.
In such high tension power sources, if a high voltage is not applied to the anode of the X-ray tube but to the cathode thereof, and furthermore the filament is heated, an extraordinary current flows between the cathode and the center metal. It is, therefore, dangerous that the X-ray tube may fail.
Several causes may be considered for the failure of the X-ray tube: high-voltage cable disconnections of the anode side, loose contact of the bushing at the anode side, problems (open circuit) in the switching element at the anode side, problems (closed circuit) in the switching element at the cathode side, and so on. For those reasons, when the open circuit is made in the anode side, the normal high voltage is applied to the cathode side and the filament is energized, this high voltage is subjected to be applied between the cathode and the center metal, so that the extraordinary current flows through them which may cause the fusing of the center metal, and the failure of the X-ray tube.
It is therefore an object of the present invention to provide a failure detection circuit of the X-ray tube power source so as to prevent the failure of the X-ray tube by detecting the failure of high tension supply to the X-ray tube.